1. Field of Invention.
The present invention relates to the field of fluid flow systems, and more particularly but not by way of limitation, to an improved characterizing linkage assembly for proportioning the flow of fluids in response to motor controls.
2. Discussion.
In the control of fuel and air mixtures to industrial furnaces, boilers and the like, there is a need to maintain proper proportions of the fuel and air over widely varying firing conditions. A number of prior art devices are known for varying inlet fuel valving and inlet air venting in response to monitored signals, such as temperature and stoichiometric parameters. For example, monitors are used to determine the free oxygen content of a stack gas and to trim the inlet air as the monitored reading varies from a set point.
As pointed out in numerous prior art publications, and as is known by persons of ordinary skill in this field, each industrial burner application will have numerous variables which take each such installation beyond the range of prediction, and thus requiring that each such installation be provided with the capability of tailoring its characterizing controls to its peculiarities over the range of its firing usage. Several prior art characterizing, or proportioning controls are as follows.
The patent issued to Maxon, U.S. Pat. No. 2,286,173, teaches a valve to proportion air and fuel to industrial burner systems in which an air gate is journaled in an air passage bore and is rotatable by a segmental arm structure. A spring loaded stemmed valve (biased closed) is supported in a fuel inlet bore. A push rod is supported to engage the stemmed valve and is operable to open same as it is pressed against the stemmed valve. Actuating means is disposed to actuate the push rod by the arm structure which supports a series of individually adjustable threaded pins carried by the arm structure to variably depress the push rod along the arc of the arm structure to vary the airfuel ratio. A flexible strip is disposed between the push rod and the threaded pins to facilitate engagement therewith.
The patent issued to Voorheis, U.S. Pat. No. 2,315,171, teaches an adjustable valve in which a series of adjusting screws provide a path to selectively depress a roller supported by an operating handle connected to a valve rod which is spring biased. Thus the object of the invention, to move the valve control element through a predetermined sequence of valve settings, is achieved.
The patent issued to Condon et al., U.S. Pat. No. 3,706,438, teaches an operating mechanism for controlling movement of a valve element. A continuous deformable channel has a pair of opposed cam surfaces supported by adjusting screws and a support member. A follower is connected to a shaft which moves a valve element between open and closed positions.
The patent issued to Spotz, U.S. Pat. No. 1,525,052, teaches an adjustable cam surface and a cam follower. The shape of the cam surface is determined by a plurality of adjustable struts which connect it to a carrying frame.
The patent issued to Tritle, U.S. Pat. No. 2,323,737 teaches a control system having a cam that is mounted for pivoting on a pin and which sections may be adjusted by means of screws.
Other patents of interest are: U.S. Pat. No. 3,425,286 issued to Ellis; U.S. Pat. No. 4,635,898 issued to Rollins et al.; U.S. Pat. No. 3,706,438 issued to Condon et al.; U.S. Pat. No. 3,685,364 issued to Turecek, et al.; U.S. Pat. No. 3,352,167 issued to Winters; U.S. Pat. No. 3,138,037 issued to Schumann; and U.S. Pat. No. 3,042,325 issued to Hughes, et al.
None of these prior art control devices provide the advantages and the novel structure of the present invention as described herein.